Physical Inactivity as Damaging to Health as Smoking

Physical inactivity has a negative global impact so severe that its adverse effects on health are comparable to that of smoking or obesity, according to a new study.

What's more, the researchers say the problem of inactivity is so bad that it should be considered a pandemic.

The study is just one in a special series of reports in the journal Lancet, timed -- in an ironic twist -- to coincide with the Olympics.

Specifically, the scientists found that inactivity was responsible for 5.3 million out of 57 million deaths throughout the world in 2008, and it caused around one in 10 deaths globally, which is comparable to the effects of smoking. The researchers also, for the first time ever, analyzed and quantified the global impact of physical inactivity on some of the world's most prominent diseases.

In the first article, researchers from Brigham and Women's Hospital and Harvard Medical School estimated that a failure to spend at least 150 minutes per week doing moderate physical activity, such as briskly walking for 30 minutes, contributed to an average of 6 percent to 10 percent of several diseases worldwide, including type 2 diabetes, breast cancer, colon cancer and coronary heart disease.

"Physical inactivity and obesity both have deleterious
effects on [these] diseases," Dr. I-Min Lee, a professor of medicine at Harvard Medical School and lead author of the study, told ABCNews.com. "Our findings described above examined the effects of inactivity, after taking into account the adverse effect of obesity. Thus, the results may be an underestimate of the true effect, since physical activity helps to control body weight."

If everyone did start participating in about the 30 minutes of moderate exercise per day, life expectancy throughout the world would increase by 0.68 years, Lee noted in the study.

Dr. George Flores, program manager for the California Endowment, weighed in on the series, and called it "timely" and "important."

Risk to health from inactivity is actually greater than the risk to health from being obese, he said.

"In the USA, the number of insufficiently active people is 50 percent greater than the number of obese people," said Flores. "That means that the opportunity to lessen risk for more people to a whole host of health problems is greater if we focus our attention on getting more people active instead of just focusing on obesity. Reducing inactivity is the single most promising opportunity to improve the health of the population at large."

Modern conveniences, including cars and computers, have contributed to the influx of physical inactivity in recent decades. Social isolation has also contributed to the shift to an inactive society.

Since the publication of the study "Actual Causes of Death in the United States," in 1993, Dr. David Katz, director of the Yale Prevention Center, said scientists have known that the three leading causes of premature death here are tobacco, poor diet and lack of physical activity.

Now, these data are becoming apparent throughout the modern world.

"Since 1993, tobacco exposure, here in the U.S., at least, has declined," said Katz. "So the relative contributions of feet and forks to the total burden of chronic disease and premature death has risen. And as labor-saving technologies proliferate across the globe, so, too, do the ill effects of sedentariness."